Hydromechanical transmission for motor vehicles



F. w. coTTERMAN 2,171,782

HYDROMECHANICAL `'IRAISRVIISSION FOR MOTOR VEHICLES slept. 5, 1939.

2 sheets-sheet 1 ogiginal Filed May 15, 1937 Sept. 5, 1939. F- W-COTTERMAN 2,171,782

A HYDROMECHANICAL TRANSMISSION FOR MOTOR VEHICLES o rviginai Filed May15, 1957 2 sheets-sheet 2 Unil- Patented Sept. 5, 1939 PATENT OFFICEHYDROMECHANICAL TRANSMISSION FOR MOTOR VEHICLES Frederick W. Cotterman,Dayton, Ohio, assig'nor ilElSSUED of one-hall"A to Bessie D. Apple,Dayton, Ohio Original application May 13, 1937, Serial No. Divided andthis application March MAR 121910 8, 1938, Serial No. 194,637

12 Claims.

This invention is a division of my copending application, Serial No.142,464, filed May 13, 1937, and relates to power transmission mechanismfor connecting a driving and driven member in 5 variable speed ratio,and particularly to that type of transmission wherein a turbine iscombined with toothed gearing'to provide a more extended range. It isparticularly adapted to automotive use.-

As is well known in the art the Fottinger fluid coupling, as applied toautomotive use, comprises a bladed impeller, driven by the engine, and abladed rotor placed adjacent and in axial align- Y ment with theimpeller, the blades being so shaped 5 thatthe uid circulates incorkscrew fashion between impeller and rotor blades. This devicefunctions merely as a coupling or clutch, and while slippage between theimpeller and rotor results in speed reduction, there is not, as is usualin speed reducing mechanism, any torque multiplication.

As a result of this shortcoming in the fluid coupling, a turbinemechanism has been proposed wherein the blades of the rotor are cut awayfor a part of their. length and replaced by blades mounted on a separatemember having means to hold it against rotation. By this separatemember, called a stator, the circulation of the fluid by the impellerbetween the rotor blades causes the D fluid to react against the statorblades whereby the rotor is driven forward at reduced speed and withmultiplied torque.

A diihculty in the turbine mechanism proposed is that it is required toact both as a clutch and 5 as a torque multiplier and these twofunctions are inconsistent.

As a clutch for instance, it is required that if the impeller isrotating say 300 R. P. M. and the. rctor 3 R. P.. M. there will besubstantially zero torque transmission, whereas if the mechanism were a.perfect torque multiplier, the torque of the impeller would in this casehave been multiplied one hundred fold in the rotor.

To obviate this di'iculty in the proposed i mechanism, means have beenadded to restrain the ilow of fluid through the impeller by blocking thespace between the impeller blades by valves. These valves are normallyclosed, but are provided with centrifugal weights which act at a lpredetermined speed to open the valves. By this means the impeller does.not actas an impeller until a considerable engine speed is reached.

An inherent diflculty in the proposed mechanism lies in the fact thatthe rotor and stator i blades cannot b so designed as to be efiicientover a very Wide range of speeds, that is, the eciency as a torquemultiplier is at its highest when the speed between the rotor and statoris that for which'the blades were designed. The eiciency, therefore, ofthe mechanism as a torque multiplier falls oi very rapidly both aboveand below the best speed. It follows that when starting a vehicle from adead stop, particularly on an up grade, the build up, i. e., theacceleration, is not all that could be desired.

As an aid to this condition, the proposed mechanism has added thereto aplanetary gear set comprising, a ring gear, a sun gear and a series ofplanet pinions in mesh with both the ring gear and the sun gear, theplanet pinion carrier being the driven member, the ring gear beingoptionally connectible by manual means either to the housing to hold itagainst rotation fora low geared drive, or to the rotor for higherhydraulic drive, the sun gear being connected to the rotor for the lowgeared drive and to the impeller for the hydraulic drive.

Now the diiculty with the proposed arrangement is to manually shift outof the low geared drive and into the hydraulic drive at the proper time,i.' e., at the time the hydraulic unit becomes eflicient enough towarrant discontinuance of the geared drive. yThere is the furtherdiculty ,that the mechanism, functioning as a clutch, never releasescompletely, whereby a manual shift into or out of a toothed connectionbecomes diflcult and necessitates further mechanism to overcome theclutch drag.

It is therefore an object of this invention to provide a combined4hydraulic and geared device of the characterdescribed with a brake forhold-r ing the rotor stationary against the impeller drag, the brakebeing operable onand oi through a mechanical, connection between theimpeller \valves .and the brake, whereby, when the valves open to causethe impeller to become effective to drive the rotor, the brakeautomatically releases the rotor to be driven, to the end that certainconnections which are preerably made to the rotor shaft when it isnon-rotative may be effected by bringing the engine to the idling speed.

In view of the limited speed range within which the hydraulicl portionof the unit described is eflcient, it is a further object of theinvention to provide a gear box whereby, rather than pull the hydraulicunit down to a ratio at which it multiplies torque at low eilici'ency, astep down in the' gear box may be made to allow the hydraulic unit tooperate at less reduction between the impeller and rotor for the sameengine to wheel ratio, with means to effect this step down easily,either when the vehicle is at rest, or when it is in motion.

In view of the further fact that the hydraulic unit of the characterdescribed is efficient for' a greater speed reduction between impellerand rotor when it is not being operated at its maximum capacity, it isfurther object of this invention to make the step down connectionthrough the gear box manually operable, whereby, when maximumacceleration, or maximum hill climbing power is notdesired, the stepdown connection need not be made.

In view of the fact that vehicle speeds must vary from 5 to 90 M. P. H.,whereas the present internal combustion engines may not be variedefficiently over more than one-fourth this range, it is a further objectof this invention to extend the ratio variation through the mechanism byemploying gear means and connections therefor, whereby there may be hadthrough the gearing, an underdrive, a direct drive and an overdriveratio, one or another of which is at all times in series with thehydraulic unit, which being responsive to both speed and torque, willvary by infinitesimal ratio changes depending on similar variations inthe balance as between the power applied 'and the vehicle resistanceinterposed thereto.

It is a further object of the invention to keep the gear box as compactand inexpensive as possible, and to this end a single gear train,comprising an internal ring gear, a sun gear,` and planet pinions, ismade by certain connections to provide an overdrive, a direct drive, anunderdrive and a reverse ratio, the overdrive being controlled bycentrifugal means, and the underdrive and reverse by manual means, whiledirect drive is a normal condition present when neither manual norcentrifugal control is being exercised.

It is a further object to provide, for the manual control, a singlepedal of simple construction through which the gearing may be operatedto underdrive, reverse, orneutral position, without removing the footfrom the pedal.

Other objects and advantages will be more readily seen as the inventionis described in detailand reference is had to the drawings, wherein;

Fig. 1 is a longitudinal vertical axial section through the transmissionmechanism.

Fig. 2 is a fragmentary section taken at 2 2 of Fig: l showing part ofthe mechanism whereby the impeller valves and the rotor brake arecompelled to operate in unison.

Fig. 3 is a fragmentary section taken at 3 3 of Fig. 1 showing severalof the impeller blades.

Fig. 4 is a fragmentary section taken at 4 4 of Fig. 1 showing thecentrifugal weights for operating the impeller valves and the rotorbrake simultaneously.

Fig. 5 is a fragmentary section taken at 5 5 of Fig. 1 showing part ofthe mechanism for operating the rotor brake.

Fig. 6 is a fragmentary section taken at 6 6 of Fig. 1 showing anotherpart of the mechanism for operating the rotor brake.

Fig. is a fragmentary section taken at 1 1 of Fig. 1 showing the frontdrive shaft clutch jaws.

Fig. 8 is a transverse section taken at 8 8 of Fig. l showing th(` frontsun gear clutch jaws.

Fig. 9 is a transverse section taken at 9 9 of Fig. 1 showing part ofthe low and reverse operating mechanism.

Fig. 10 is a fragmentary horizontal section taken at I0 I0 of Fig. 1showing the construction of the low and reverse shifting collar.

Fig. 11 is a transverse section taken at H Il of Fig. 1 through theplanetary gearing and the clutch jaws of the planet pinion carrier.

Fig. 12 is a transverse section taken at I2 |2 of Fig. l showing therear drive shaft clutch jaws and a part of the mechanism for connectingthe gearing to provide an overdrive.

Fig. 13 is a transverse section taken at I3 |3 of Fig. 1 through thecentrifugal mechanism for effecting the overdrive connection.

Fig. 14 is a diagrammatic view showing how adjacent faces of clutch jawscarried by the drive shaft and by the sun gear must be beveled to insuresmooth shifting into direct drive.

Fig. 15 is a diagrammatic view showing how adjacent faces of otherclutch jaws carried by the sun gear and those supported in the housingare beveled to insure smooth shifting into low gear and overdrive. y

Fig. 16 is a diagrammatic view showing how adjacent faces of clutch jawssupported in the housing and on the front of the planet pinion carrierare beveled to insure smooth shifting from direct drive to reverse.

Fig. 17 is a diagrammatic view showing how adjacent faces of clutch jawsin the tail shaft cylinder and on the outside of the ring gearcarrierare beveled also to insure smooth Ashifting from direct drive toreverse.

Fig. 18 is a diagrammatic view showing how adjacent faces of clutch jaws'on the front of planet pinion carrier and in the tail shaft cylinderare beveled to insure smooth shifting from reverse back to direct drive.

Fig. 19 is a diagrammatic view showing how adjacent faces of clutch jawsat the inner periphery of the ring gear carrier and on the rear end ofthe drive shaft are beveled also to insure smooth shifting from reverseback to direct drive.

Fig. 20 is a diagrammatic view showing how adjacent faces of the clutchjaws on the front of the drive shaft and on the hub of the sun gear arebeveled also to insure smooth shifting from direct drive to reverse.

Fig. 21 is a diagrammatic view showing how adjacent faces of clutch jawson the outside of the ring gear carrier and on theinside of the tailshaft cylinder are beveled to.insure smooth shifting from direct tooverdrive.

Fig. 22 is a diagrammatic view showing how adjacent faces of clutch jawscarried at the inner periphery of the rear of the planet pinion carrierand on the rear end of the drive shaft are beveled to insure smoothshifting from direct to overdrive.

Fig. 23 is a diagrammatic View showing how adjacent faces of clutch jawsin the tail shaft cylinder and on the front of the planet pinion carrierare beveled Ato ,insure smooth shifting from overdrive back to directdrive.

Fig. 24 is a diagrammatic View showing how adjacent faces of clutchjawson the rear end of the drive shaft and onl the inner periphery ofthe ring gear carrier are beveledalso to insure smooth shifting fromoverdrive back to direct.

Fig. 25 is a fragmentary section taken at 25-25 of Fig. 1 through thecentrifugal mechanism for effecting the overdrive connection.

Fig. 26 is a fragmentary section taken at 26-26 of Fig. 13 through thecentrifugal mechanism for effecting the overdrive connection.

Fig. 27 is a side elevation of the device to a reduced scale showing themanual control.

Where a reference character is used to designate a certain part in anyview, it is not used to designate a different part in any of the views.

Construction The housing provided to contain the mechanism is composedof three sections. The forward section 28 contains the hydraulic unit,the rearward section 30 contains the gear set and the centrifugalmechanism for connecting the gearing for overdrive, and the middlesection 32 contains the manually operable mechanism for effectingunderdrive, neutral and reverse. Screws 34 secure the front and middlehousing sections together and screws 35 secure the middle and rearsections together.

Within the forward section, the crank shaft 36 of an engine 38 has theimpeller plate 48 secured thereto by the bolts 42 and nuts 44. Theimpeller 46 has blades 48 and is secured to the plate 48 by screws 58.

The rotor comprises a main body 52, a core 54 and blades 56 arranged inVtwo stages. An impeller cover 58 is secured to the impeller 46 by thescrews 60. The cover 58 ts as closely around the rotor blades 56 as willpermit rotation at different speeds between the two parts.

At the rearward side, the rotor blades 56 and a small section of thecore54 are out away to admit the stator blades 62. The stator blades 62 aresupported on the stator body 64, and are so angled that movement of auid between the rotor blades 56, in the direction of the arrow 66,impinges on the stator blades to drive the rotor forward, by forwardbeing meant clockwise when standing at the left of the drawing.

The rotor shaft 68 has rotative bearing at` the forward end of. thebearing bushing which is press fitted in the crank shaft 36, and at therearward end in the bearing bushing 1| which is press fitted in the tailshaft 13. External splines 12, Fig. 6, fit between internal splines 14of the rotor hub whereby the shaft and rotor always rotate in unison. Acollar 16 is tted to be slidable axially on the shaft 68. Pins 1 1 pressfitted in the collar are slidable in holes in the crank shaft 36 wherebythe collar is compelled to rotate with the crank shaft. Collar 16 isprovided externally with a coarse pitch thread 18. A gear 80 isinternally threaded at 82 to t over the threads 'I8 of the collar.

Oblong slots 84 in the gear clear the nuts 44 so that the gear may haveslight rotative movement with respect to the plate 40. Arcuate openings86 through the gear receive the springs 88, and studs 90, the shanks ofthe studs being riveted in the plate 40 as at 9|. The springs 88 alwaysurge the ear 88 in the direction of the arrow 93 with respect to theplate 40.

Between the impeller blades 48 are the butterfly valves 92. The valvestems 84 are squared at 96 where they pass through the valves, roundedat98 and |88 where they have bearing in the impeller, and squared to asmaller size at |02 where they pass through the centrifugal weights |84.Pinion segments |06 are integral with the stems 94 and are in constantmesh With'the gear 80.

A forwardly extending hub |88 having a flange |89 is centrifugallysecured to the front of the middle housing section 32 by screws ||0. Theoutside of the rotor hub 'l5'has rotative .bearing of flanged hub |88.

in a bushing ||2 press fitted into the front end The stator body 64 isheld by a key ||4 to the stator hub ||6 which is internally formed toreceive the combination roller bearing and roller clutch ||8. Theflanged hub |08 is externally formed for the combined clutch and bearingwhich permits the stator to rotate forwardly but not backwardly. I

A thrust bearing holds the rotor in its forward position. A felt sealwasher |22 held by retaining members |24, |26 and |28 keeps thehydraulic uid from leaking out into the housing section 28.

At the rearward end the flanged hub |08 is internally tapered to receivethe brake 4cone |30 which is normally held engaged by the spring |32.

A washer |33 held at its periphery between the flanged hub |08 and themiddle housing section 32, receives the reaction of the other end of thespring. The washer |33 also limits end movement of the rotor shaft 68.

The externalsplines 12 of the rotor shaft 68 are spaced as for sixsplines but two of the splines have been cut away, (see Fig. 6), and thespace thus made between internal splines 14 of the rotor hubslidably'receive the keys |34. rThe keys |34 are notched attheir'frontend at |36 and the washer |38 is correspondingly notched to fit over thekey ends. The notched ends of the keys are preferably brazed to thewasher |38.

The cone |30 has internal splines |48 slidably fitted to the externalshaft splines 'l2 whereby the cone always rotates with the rotor shaft68. As long therefore as the spring |32 is expanded, the friction of thecone |30 in the tapered end of the hub |08 keeps the rotor 52 and theshaft 68 from rotating. When, however, the centrifugal weights |04 arecaused by sufficient impeller speed to fly out and open the valves 92,the segments |06 turn the internally threaded gear 80, whereupon theexternally threaded collar 'i6 is moved axially rearward against thewasher |38 which pushes the slidably fitted keys |34 against the cone|30 and forces it out of contact with the tapered opening inthe hub |88.The opening of the Valves 92 for mak-ing the impeller effective as such,musttherefore always occur simultaneously with the freeing of the rotor52 by the brake cone |30. v

In the forward half of the rear housing section 38 is the planetary geartrain. .The sungear |42 has a long forwardly extending hub |44 to theinterior of which are press fitted the bearing bushings |46 and |48which are runningly fitted to the rotor shaft 68. Six planet pinions |58are equally spaced about, and in mesh with the sun gear. The planetpinion carrier comprises a front section |52 and a rear section |54between whichI the pinions are held. Planet pinion studs |56 are rivetedin the vrear section and held in the front section by the nuts |58.Bearing bushings |68 are press fitted to the inside of the pinions andrunningly tted over the studs.

Ihe gearing preferably has staggered herringbone teeth so there will beno end thrust under load and therefore, to facilitate assembly, the

, ring gear comprises a front half |62 and a rear bushing |12 which hasrotative bearing on thev hub |44 of the sun gear. An end thrust washer|13 is a press t on the sun gear hub |44 and extends over the ends ofthe sun gear teeth whereby the washer always rotates with the sun gearand insures that when the sun gear moves axially on the rotor shaft itmust take the carrier with it and viceversa. The rear section |54 of theplanet pinion carrier has press fitted therein the bearing bustling |14,which has rotative bearing on the rotor shaft 68.

'I'he ring gear carrier |66 isprovided with a press fitted bearingbushing |16 at the forward end and another bushing |18 at its rearwardend, the bushing |16 being runningly fitted over the rear carriersection |54 and the bushing |18 runningly fitted over the outside of therotor shaft rear clutch member |82.

A split washer |83 is clamped at its periphery between the rear half |64of the ring gear and the ring gear carrier |66. The split washer |83extends into a groove in the vrear section |54 of the planet pinioncarrier, its purpose being to restrict relative axial movement betweenthe planet pinion carrier and the ring gear carrier.

A ball bearing |84 supported in the rear housing section 30 providesrotative bearing for the tail shaft 13, the bearing being held to theshaft by the screw |88 acting through intermediate parts |90, |92, |94and |96. The forward end of the tail shaft has a flange |98.

The overdrive governor frame 200 has a flange 202 at the rear endconcentrcally held tothe tail shaft flange |98 by the screws 204 (seeFig. 13), at the forward end the governor frame is bored to slidinglyreceive theV tail shaft jaw clutch ring 208. Ring 208 has a series ofcircumferentially spaced ears 203 movable axially in the slots 205 andheld positioned midway of the length of the slots by a pair of plungers206 with heads 201 backed up by springs 209. For convenience inmachining and assembly the rings 2| I, 2| 3 and 2|5 are separate fromthe governor frame 200 and are held thereto by the screws 2|0 (see Fig.12)

It will be seen that if the jaw clutch ring 208 is moved axially ineither direction it will snap' back to the position shown. The governorframe 260 is provided internally with the bearing bushing 2|2 which isrunningly fitted over the ring gear carrier |66. Rotation of the ringgear carrier in this bushing is had only while underdrive is in effect,and never during direct drive, overdrive or reverse. The tail shaft 13is held against rearward axial movement by the ball bearing |84 andagainst forward axial movement by the washer 2|4 which rests against ashoulder on the rotor shaft 68.

While neither the tail shaft assembly which includes the tail shaft-13,governor frame 200 and clutch ring 208, nor the rotor shaft 68 have anyaxial movement in the housing, the entire gear assembly including, theplanet pinion carrier and ring gear carrier, are slidable axialiy on therotor shaft, rearwardly to take up the space 2|6 and forwardly to takeup the space 2|8. This axial movement of the gear assembly is utilizedto effect various gear connections necessary to the different ratios.

Endwise slidable on the long sun gear hub |44 is a. sleeve 220 having atits forward end a :mail ange 222 and endwise slidable on the sleeve 220is a second sleeve 224 having a large flange 228, and endwise slidableon the sleeve 224 is the shifting collar 228 having. a shifting groove230 around it. The collar 228 has two oppositely disposed integral keys232 extending inwardly into slots which extend through the sleeves andthe sun gear hub. Because of the keys the sun gear hub |44 and thesleeves 220 and 224 must always rotate in unison.

The slots- 234 and 238 which extend through the sleeves 220 and 224 arelonger than the keys 232 so that the keys may be moved axially to someextent in both directions from the position shown in the drawingswithout moving the sleeves directly. When, however, the collar 229 ismoved forwardly or rearwardly, the springs 2 38 or 240 are energized andthe sleeves 220 and 224 are urged forwardly or rearwardly by thesprings, depending on the position of the collar 228. A spring ring 229is placed in a groove in the sleeve 220.

This ring prevents the flanges 222 and 226 from moving farther apartthan shown in the drawings, but does not prevent them moving closertogether against the force of the springs 238 and 240. This feature isimportant in the functioning of the mechanism as will hereafter appear.

'I'he slots 242 through the sun gear hub 44 are longer than the keys 232only at the rear of the keys. For this reason the collar 228 may moverearwardly without moving the hub |44. The movement however compressesthe spring 240, but if the collar is moved forwardly, it must drag theentire gear assembly forwardly with it. To facilitate assembly, thecollar 228 is made in halves held together by the screws 244, (see Fig.9) extending through ears 245.

A shifting fork 246 is swingable by the splined shaft 248 which hasrotative bearing in the hubs 250 and 252 of the middle housing section32. Rollers 254 (see Fig. 9) are rotatable on studs 256 secured 'in thefree ends of the fork. 'Ihe rollers 254 fit the groove 230 closely butrunningly. 'I'he forward side of the shifting fork 246 is fiattened at258 and a hollow plunger 260 is pressed against the flattened surface bythe heavy spring 262.

The fork hub is further cut away at 264 so that the springs 262 need notbe compressed as much when the collar 228 is moved forwardly as when itis moved rearwardly. The reason for desirihg this dierence in pressurewill later appear.

The overdrive governor frame 200 has two ribs 265, each thick enough tocontain a plunger 266 backed up by a heavy spring 268 and a plunger 210backed up by a lighter spring 212. The frame also carris ribs 214, (seeFig. 12) which terminate at their rear edges in hinge ears 216 (seeFigs. 13 and 26).

The governor weights 218 each have a pair of hinge ears 280 and 282 (seeFig. 25), extending forwardly between the frame ears 216. Hinge pins 284extend through both the frame ears and the weight ears to hingedlysupport the weights on the frame.

The hinge ear 280 of each weight 218 is prolonged to form the arm 286which, near its free end, has a hub 288 which carries the stud 290,

having a roller 292 rotatable thereon. The hub 288 reaches through anarcuate slot 294 in the governor frame 200 and holds the roller 292 in acircular groove 298 in the rear end of the ring gear carrier |66 wherebyinward or outward movement of the weight 218 rocks the arm forward orrearward and thereby moves the gear assembly forward or rearward formaking diff erent connections for different ratios.

At the extreme free end of each arm 286 is the segment 288 so shapedthat the detent plunger 308 backed up by the spring 302 resists swingingof the arm about the hinge pin in the direc- 75 tion caused by outwardmovement of the weight, but does not resist swinging of the arm aboutthe hinge pinin the direction caused by inward movement of the weight.

A notch 304 in the edge of the segment tends to keep the arm located inits rearward position when the plunger 300 is pressed into the notch bythe spring 302.

Outward movement of the weights 218 is resisted by the heavy springs 268acting through plungers 266 and by the springs 302 acting through detentplungers 300, while inward movement of the weights is resisted only bythe light springs 212 acting through plungers 210. Outward movement ofthe weights 218 is caused only by centrifugal force, while inwardmovement occurs only when the gear assembly is drawn by forward movementof the collar 228 acting through the keys 232 against the front end ofthe slots 242 of the sun gear hub |44. The flanges |98 and 202 arenotched at-303 to clear the weights 218.

On the forward end of the long sun gear hub |44 are formed the clutchjaws 304,. On the forward end of the sleeve 220 are formed the clutchjaws 306. The faces of the jaws 304 are beveled at 308, Fig. 20, whilethe faces of the jaws 306 are beveled just oppositely as at 3|0, Fig.14.

Integral with the rotor shaft 68 are three segmental lugs (see Fig. 7),the inner halves 3|2 of which are thicker (see Fig. 1), then the outerhalves 3| 4', the inner halves having their faces beveled as at 3|6,Fig. 20, and the outer halves having their faces beveled justoppositely, as at 3|8, Fig. 14.

The sun gear jaws 304 are adapted to be received in the spaces betweenthe rotor shaft jaws 3|2 when the gear assembly is drawn forward bymeans of the collar 228, while the sleeve jaws 306 are adapted to bereceived in the spaces between the rotor shaft jaws 3|4 whenever thespring 238 is energized to a greater extent than the spring 240 which isthe condition present when the mechanism is as shown in Fig. 1 of thedrawings, i.e., with-jaws 306 and 3|4 meshed.

As above described there are two sets of clutch jaws, both forconnecting the sun gear to the rotor shaft, one set havingthe jaw facesbeveled in one direction and the other set having the jaw faces beveledopposite to-the rst set, the reason being that, under one drivingcondition, the sun gear must connect tothe rotor shaft when the rotorshaft is just passing the sun gear in speed, while under another drivingcondition the sun gear must connect to the rotor shaft'when the sun gearis just passing the rotor shaft in speed.

Around the periphery of the flange 226 are the external clutch jaws 320.The rear faces of these jaws are beveled as at 322, Fig. 15. Clampedbetween the middle and rear housing sections 32 and 30 by the screws 35is a clutch ring 324 having internal jaws 326 beveled on their front andrear faces as at 328 and 330, Figs. 15 and 16.

Within the tail shaft clutch ring 208 are three axially spaced sets ofjaws, the forward set 332, the middle set 334- and the rear set 336. Theforward set 332 has its front end rear faces beveled as at 338 and 340,Figsf18 and 23. The

middle set 334 has its front and rear faces bevthe planet pinion carrierare the jaws 348 (see Fig. 11), beveled on. their front and rear facesas at 350 and 352, see Figs. 16, 18 and 23.

At the periphery of the ring gear carrier |66 are the jaws 354, beveledon their front faces as at 356, but plain on the rear faces as at 358,Figs. 17 and 21.

On the outside of the rear section |54 of the planet pinion carrier arethe jaws 360, beveled on their rear faces only as at 362, Fig. ,22.

On the inside of the ring gear carrier |66 are the jaws 364 (see Fig.'12), beveled on the front and rear faces as at 366 and 368, Figs. 19and 24.

On the outside -of the rotor shaft rear clutch member |82 are the jaws310, straight on their iront faces as at 312 and beveled on their rearfaces as at 314, Figs. 19, 22 and 24.

The rotor shaft 68 has splines 316 on the rear end (see Fig. 13), andthe clutch member |82 has internal splines 311 axially slidable over theshaft splines. A hole 318 is drilled in the rear end of the shaft 68 anda slot 380 extends crosswise through the shaft and hole. A rectangularbar 382 is freely fitted to the slot and is held to the rear of the slotby the spring 384 which is within the hole 318. The bar 382 has onlyabout half the axial dimension of the slot, whereby the bar may moveaxially forward against the stress of the spring. The bar 382 not onlyrests against the rear edge of the slot 380, but its outer ends restagainst the ends of two of the internal splines 311 of the clutch member|82.

Surrounding the end of the shaft 68 where there are no splines is thespring 386, one end .of which rests against the washer 2 |4 and theother against the ends of the shaft splines 316 as well as the ends ofthe internal splines 311.

The structure provides means whereby the clutch member |82 isresiliently held in the axial location shown. If it is moved axiallyforward, the spring 384 will be compressed, but the spring 386 will notfurther expand, and if it is moved axially rearward, the spring 386 willbe compressed but the spring 384 will not further expand. The clutchmember |82 will therefore vsnap back to the exact position shown nomatter in which axial direction it has been moved. i

Rigidly secured to the outer end of the splined shaft 248 is the pedal388 (see Fig. 27). The shaft 248 and the hub 252 (see Fig. 9) areprolonged suciently to locate the pedal in the position occupied, inconventional practice, by the clutch pedal, i. e., in the positionsuitable` for operation with the drivers left foot. Downward pressure onthe pedal by the toe will move the collar 228 rearward to effect theunderdrive connection, while downward pressure on the pedal by the heelwill move the collar forward for reverse connection.

The floorboard line is at 390 and the toeboard A pocket 394 is depressedin the oorboard, somewhat wider than the pedal, at the heel end thereof.complete disconnection of the rotor shaft from the tail shaft is hadwhen the heel end of the pedal is pressed half way down, and, in orderto facilitate gauging the halfway position, the projection 396 is formedin the pocket 394. By allowing the foot to slide heelward on the pedal388 until the back of the heel contacts the rear Wall 398 cf the pocket,the bottom of the heel will project overthe rear end of the pedal andwill therefore when pressing downward on the pedal, en-

'counter the projection when the half way down position of the heel endof the pedal isI reached.

A neutral position involving This position may be required in coldweather for warming the engine when it is desired to rotate it fasterthan the speed at which the impeller valves open and movement of thevehicle begins.

Proportion While the mechanism shown may be proportioned for use withany horsepower and vehicle weight within reason, some suggestion as tothel proportion for a given vehicle may preferably be given.

If the largest dimension of the housing 28 is taken as 151/2" and the:other parts made to the same scale, the mechanism will be suitable foran engine of around 100 H. P., in a vehicle of approximately 3500 poundweight.

The planetary gearing are 16 pitch 20 degree pressure angle, 14 degrees55 minutes helix angle. The ring gear has 60 yteeth on a pitch diameterof 3.88087; the sun gear 30 teeth on a pitch diameter of 1.9404; and theplanet pinions 15 teeth on a pitch diameter of .9702".

The underdrive ratio, provided by making the ring gear the driver, theplanet pinion carrier the driven, and the sun gear the stationarymember, will then be R+s 6c+3o R 60 11/2 rotor shaft revolutions to onetail shaft revolution.

The overdrive ratio, provided by making the planet pinion carrier thedriver, the ring gear the driven and the sun gear the stationary member,will be 2 rotor shaft revolutions to produce 1 tail shaft revolution.

With a 4 to 1 rear axle and the hydraulic unit loaded so as to pull itdown to a ratio of 2 impeller revolutions to 1 rotor revolution, whichis within the efficient range as a torque converter, the totalengine-to-wheel ratio through underdrive would be 2 4=12; through directdrive 2 1 4=8: and through overdrive 2 2s 4=51A;. But in either of thesegear connections, the torque converter would gradually, as the enginewas able to increase its speed under the load, change from 2 to 1, to 1to 1, whereupon the engine-to-wheel ratio would be, for underdrive 6 to1; for direct 4 to 1, and for overdrive 2% to 1.

The range of engine-to-wheel ratio change is therefore usually somewherebetween 12 to 1 and .2% to 1, depending on to what Aextent the ratio ofthe hydraulic unit is pulled down, or allowed to go up by variationbetween the power being generated and the vehicle resistance being en-|04, and the springs 88 and |32 are so propertioned that the weights flyout and open the impeller valves and release the rotor brake at about600 engine R. P. M.- This may of course be varied to suit individualengines.

In the gear box, the centrifugal weights 218 and their restrainingsprings 268 and 302 are preferably so proportioned that the weights willmove to connect for overdrive ratio at around 501 M. P. H. However,since the rear axle ratio must be varied somewhat from the 4y to 1 valuegiven, becoming greater as the vehicle weight is greater and the enginepower less, so the overdriveratio may profitably be varied, i. e., tocome in at a lower speed if the proportion of engine power to vehicleweight justifies with the axle ratio selected.

Operation The normal condition of the mechanism, i. e., the conditionwhich exists when the engine is at rest or operating below 600 R. P. M.is that shown in the drawings, where the centrifugal weights |04 of thehydraulic unit are in their in" position and the rotor brake |30 isapplied, and where the gear mechanism iscoupled for direct drive, i. e.,for connection between the rotor shaft and tail shaft which compels themto revolve at the same speed. This coupling exists by virtue of the factthat the sun gear and the ring gear are both connected to revolve withthe rotor shaft, and the planet pinion carrier is connected to revolvewith the tail shaft, no member being held stationary.

The greater percentage of all forward driving will be done with the gearmechanism in direct drive as shown. If, for instance, a driver isstarting the vehicle on a substantially level road and is content withgood, but not maximum acceleration, he need only depress the engineaccelerator whereupon the engine will first increase to 600 R. P. M.open the impeller valves and release the rotor brake, thereby drivingthe rotor at a less speed and greater torque than the engine.

A'hydraulic torque converter simi.ar to that herein shown has alreadybeen developed by others toa degree which provides torque multiplicationsomewhat better than is had with the second gear of a conventional gearbox. Inasmuch as many drivers of conventional vehicles start from a deadstop in second gear, such drivers at least would be satisfied with theacceleration obtainable through the hydraulic unit herein shown withoutfurther torque multiplication through the gear mechanism.

Other driving conditions, however, require the use of the gearing, asfor instance, where the driver has started the engine in the usualmanner and it is cold, and he desires to speed up the engine beyond 600R. P. M. to warm it without driving the vehicle. In this case he allowshis ioct to slide heelward on the pedal until the back of his heeltouches the wall 398 (see Fig. 27) He then presses the heel end oi thepedal 388 down until the bottom of his heel strikes the projection 396.In doing this he has drawn the gear assemblyA forward with the collar228 until the jaws 348 of the carrier section |52 are out of engagementwith the tail shaft jaws 332 but not far enough to nave engaged thestationary jaws 326. Similarly the jaws 364 cf the ring gear carrierhave moved out of engagement with the jaws 310 of the clutch member |82.The sun gear iaws 304 have moved forward but .not

vthe vehicle. To do this he rst lowers the engine R. P. M to the idlingspeed by releasing the accelerator pedal, then places his foot on thepedal 338 as shown in Fig. 27 and presses the heel downward. To make thereverse connection the jaws 304 of the sun gear must mesh with the jaws312 of the rotor shaft, the jaws 348 of the planet pinion carrier .mustmesh with the jaws 326 of the stationary ring, and the jaws 354 of thering gear carrier must mesh with the jaws v 334 of the tail shaft ring.The connections shown in the drawing between the planet pinion carrierand the tail shaft and between the ring gear carrier and the rotor shaftwill, of course, be first unmade.

Since it is highly improbable that all these sets of jaws to be meshedwill be in meshing alignment when the heel is pressed downward, itfollows that the faces of at least some of the jaws will come together,but power is now applied to turn the rotor shaft, whereupon the firstset to be meshed will have relative movement as indicated by the arrowsin Fig. v20, the second set will have relative movement as indicatd bythe arrows in Fig. 16, and the third set have relative movement asindicated by the arrows in Fig. 17.

The space 2|8 (see Fig. 1), through which the jaws 304 must move toreach the jaws 3|2 is slightly less than the spaces through which theother jaws to be meshed must move, so that the rotor shaftmotion willalways start the sun gear rotating first.

Rotation of the remaining jaws to be meshed will naturally follow, and,the faces being beveled as shown, the jaws will move, each down thebeveled faces of the other into mesh, if a slight foot pressure ismaintained after the accelerator is depressed. Should the jaws 348become aligned with the jaws 326 before the jaws 354 become aligned withthe jaws 334, the jaws 348 may at once enter because of the yieldablemannerin which the jaws 334 are held positioned by the springs 200 andplunger heads 201.

When the gear assembly is drawn forward as above explained to make thereverse connection, the ring gear carrier groove 296 (see Fig. 1), is,of course drawn forward vlith it. The roller 292, being in the groove296, swings the arm 286 in the direction of the arrow 402, Fig. 26, andcauses the weight 218 to swing inwardly against the plunger 210 andspring 212, Fig. l. The low speed at which a vehicle is driven backwardproduces a very slight centrifugal force in the weights 218 which mustbe overcome by the pedal along with the force of the spring 212.

In order to lessen the force necessary to press down the pedal forreverse connection, the shifting fork 246 is cut away as at 264, so thatthe spring 262 is compressed less in pressing the pedal 388 with theheel than when pressing it with the toe. The springs 238, 262 and 212,each provide part of the resistance offered to the pedal in making thereverse connection.

Assume that the vehicle has been moved backwardly as d'esired and thepressure is removed from the pedal to allow it to return to the normalposition shown in Fig. 27. This should remake the direct driveconnection. The expansion of rgear jaws 364 with the rotor shaft jaws310.

. acceleration.

the springs 238 and 262 immediately return the pedal and the collar 228,but unless -both sets of jaws which have to be reengaged are in meshingalignment, which is unlikely, the spring 212 may not instantly expand,but will hold the faces of 5 the jaws together resiliently until theymay mesh. The jaws which must be remeshed when shifting out of reverseback to direct are, the carrier jaws 348 with the tail shaft jaws 332,and the ring When release of the heel pressure from the pedal hasallowed the faces of these two sets of jaws to be resiliently pressedtogether, the power may be applied to turn the rotor shaft, whereuponrelative motion of the jaws 348 with 332 and of the jaws 364 with 310will be according to the arrows in Figs. 18 and 19Arespectively. Byreference to Figs. 18 and 19, it will be seen that the faces of the jawsseeking engagement are so beveled that when they are held togetherresiliently and rotation started, the jaws will slide down the inclinedfaces into mesh.

If, during the above reentry, the jaws 348 and 332 are aligned forreentry with each other before the jaws 364 and 310, or vice versa, thefact that the jaws 332 and the jaws 310 are yieldably held to thepositions shown by springs 209 and 386 respectively, will permit eitherto mesh ahead of the other.

It will be apparent that it would not be best to have two sets of jawswhich must be meshed at the same time unless each set was independentlysprung, inasmuch as a rotating condition might be had where, when eitherset of jaws were aligned to enter, they would be held apart because ofthe fact that the other set was at that time misaligned. It is at leastapparent that entry of two sets may be more readily made if each isindividually sprung.

Assume the drivernow wishes to use underdrive to move the vehicleforward with maximum For making this connection he presses the pedal 388all the way down with the toe end of his foot. The rst result had is,that the collar 228 moves rearward and its keys 232 move in spaces 234,236 and 242. The gear assembly does not move because the springs 268 and212 acting on the plungers 266 and 210 hold the arm 286 and roller 292rigid. The slots 242 in the sun gear hub are of such length that, atmaximum pedal depression, the keys 232 just touch the rear ends of theslots, but the slot 234 is so much shorter than the slot 242 that lthemaximum pedal depression causes the keys 232 to pull the jaws 306 halfout of mesh with the jaws 314. Now by considering Figs. 14 to 2,4, itwill be seen that the amount of bevel on the sides of the beveled jawsis one-fourth the whole j aw thickness. It follows that when a pair ofsuch jaws are meshed half way or less they drive in one direction butwill overrun in the other. They will drive in one direction but rafchetover in the other direction up to half way mesh, but either one willdrive both direct-ions after it is more than half way meshed.

Besides having pulled the jaws 306 half out of mesh with the jaws 3|4and made a one way drive of them, the pedal depression also greatlyincreased the stored energy in the spring 240 and caused it toresiliently hold the faces of the jaws 320 against the faces of the jaws326.

If the power is now applied, the rotor shaft will drive the ring gearbecause the rotor shaft jaws 310 and ring gear jaws 364 are fullymeshed. The vehicle resistance now tries to hold the tail shaft, andconsequently the planet pinion carrier,

from rotating, which results in the sun gear starting to rotatebackwardly, which it may do because the jaws 306 may ratchet backwardlyover the jaws 3| 4 (see Fig. 14), their relative movement beingaccording to the larrows Fig. 14, but after about one-sixth revolutionof the sun gear, the jaws 320 also starting backwardly (see Fig. 15),will have followed the inclined faces 322 and 328 and entered into mesh.

Now the snap ring 229 is so placed that when the jaws 306 are pulledhalf way out of mesh the jaws 320 may go half way into mesh but notfarther, and when the jaws 320 move more than half in, the jaws 306 aredrawn more than half out, so that by the time the jaws 320 are fullymeshed, the jaws 304 are fully unmeshed.

The foregoing described a shift from direct to underdrive when thevehicle was at rest, but it is also desirable that a shift from directto underdrive may easily be made at high vehicle speed, as for instance,when a steep grade is encountered.

In such a case the operator preferably rlrst releases theacceleratorpedal momentarily, then depresses the toe end of the controlpedal, thereby pulling the jaws 306 half out of mesh as well as pressingthe faces of the jaws 320 resiliently against the faces of the jaws 326.

The accelerator being released, the vehicle movement tries to rotate thesun gear forwardly but the half meshed jaws 306 prevent the sun gearrotating forwardly `faster than the engine, that is, they drive theengine by vehicle momentum. The jaws 320, moving forwardly will ofcourse ratchet over the jaws 326 (see Fig. 15), until power is appliedto Ithe engine, whereupon the sun gear tries to rotate backwardly, andwhen it does, the full meshing of the jaws 320 and 326 takes place forunderdrive as before explained. It will be seen that in the transitionperiod there was no free wheeling, that is, the vehicle still drove ltheengine after the pedal was operated and the engine drove the vehicle assoon as power was applied. There is no point at which the engine andvehicle are completely separated as they are in the shift of commonpractice.

Now if, while operating in underdrive at high speed, it becomesdesirable to return to direct drive, the control pedal is merelyreleased and the collar 228 will return to the normal position shown inthe drawings. Although the springs 238 are now placed in much greaterstress than the springs 240, the jaws 320 may not move out of mesh withthe jaws 326 until the accelerator is sufficiently released to relievethe friction between the driving surfaces of the jaws.

When, however, the tension between these driving faces is relieved, the@jaws 320 will be drawn half way out of mesh, by engagement of theforward end of key 232 with the forward end of the slot 236, andthefaces of the jaws 306 pressed resiliently into contact with the faces ofthe jaws 314. Inasmuch as the sun gear was non-rotative when theaccelerator was released, the jaws 3I4 may ratchet over the non-rotatingjaws 306 (see Fig. 14), even though they are half meshed, until theengine speed reduces to a point where the vehicle tries -to drive theengine, whereupon the sun gear will try to rotate forwardly and the jaws306 will slide down the inclined faces of the jaws 3|4 and into mesh.When they are halfway meshed, the spring ring 229 encounters theshoulder in the sleeve 236 and the jaws 320 are pulled clear out of meshas the jaws 306 go clear into mesh.

Theoverdrive gear connection will be made automatically whenever theaccelerator is released if the vehicle is .moving faster than 50 M. P.H. The operation of shifting up to overdrive is as follows:

When the gearing is in direct drive as shown in the drawings, and thevehicle speed exceeds 50 M. P. H., the centrifugal force of the weights218 must be suflicient to overcome the governor springs 268, the detentspring 302 and the pedal return spring 262. If the accelerator is nowreleased, so as to remove the friction from the jaws which are carryingthe load, the weights will move out and, through the arms 286 androllers 292, draw the entire gear assembly rearward. The straight faces358 of the ring gear jaws 354 are pressed against the straight faces 346of the rear tail shaft jaws 336 (see Fig. 21).

Similarly, the straight faces 362 of the planet pinion carrier jaws 360are pressed into contact with the straight faces 312 of the rear driveshaft jaws-310 see Fig. 22). Since all of these jaws are revolving atthe same speed when pressed together there is no necessity of having thefaces of these jaws beveled to permit overrunning, but

unless these two sets of jaws are aligned for entry, the jaws 336 and310 will be displaced rearwardly, against the resistance of springs 208and 386 respectively, a distance equal to their thickness, in order thatthe weights 218 may move all the way out at once.

The weights in thus moving out and moving the gear assembly rearward,also draw the collar 228 rearward and the toe end of the control pedal388 down exactly as they are operated manually when shifting from directto underdrive, the jaws 3l4 being pulled half out of mesh to ratchetingposition and the jaws 320 being resiliently held against the jaws 326.

Dropping of the engine speed now produces -relative movement of the jaws3I4'and 306 as in Fig. 14, and relative movement of the jaws 320 and 326as in Fig. 15. The remaining jaws 354 with 336, and 360 with 310 whichare pressed together resiliently may drive by friction suiciently toturn the jaws 320 to meshing position (see Fig. 15), or, if they slipever so slightly, they will mesh positively and drive directly. Ineither event, a pause of a second or two after the weights 218 move outwill cause all connections for overdrive to be made. When the vehiclespeed is lowered to about 4 M. P. H., which may be made as much less asdesired by using a stronger spring 302 back of the detent plunger 300,the weights', upon release of the accelerator pedal, will move in,returning the gear assembly and the collar 228 and pedal 388 to thenormal position shown in the drawings. Three sets of jaws' are againpressed together resiliently, 306 against 3I4 (see Fig. 14), 348 against332 (see Fig. 23), and 364 against 310 (see Fig. 24). Ratcheting betweenthe several jaws of each pair will occur, the relative movement being asindicated by the arrows in Figs. 14, 23 and 24, until the rotor shaftspeed again is brought up to the tail shaft speed which may be done by atouch of the accelerator pedal.

While 'the mechanism herein shown and described includes a hydraulictorque converter with a mechanical gear-set in series and is thus shownin order to disclose a complete operative structure, the'followingclaims are drawn tothe novel features of the hydraulic unit only, claimsto the gear-set being contained in the parent application hereinbefore.referred to. f

I claim- 1. In a fluid coupling of the Fottinger type comprising, animpeller and a rotor, the combination with means operative tosubstantially block circulation of the uid, braking means to hold therotor non-rotative While said .blocking means is operative, and meansresponsive to impeller speed to simultaneously operate the blockingmeans to inoperative position and the braking means to releasedposition.

2. In power transmission mechanism, an impeller, a -rotor adapted to bedrivenby said impeller, valve means for closing the spaces between theimpeller blades, a brake for holding the rotor against rotation, speedresponsive means for opening said valve means at a predeterminedimpellerspeed, and means connecting said valve means and said brake wherebyopening said valve means releases said brake.

3. A fluid coupling of the Fottinger type comprising an impeller and arotor in combination with means applicable to substantially blockcirculation of the uid, braking means applicable to hold the rotornon-rotative while said blocking means is applied, and a centrifugaldevice ro a centrifugal device operative at a predetermined speed tosimultaneously open the valve means and release the brake.

5. Fluid transmission mechanism of the character described having animpeller and a rotor in combination with means normally retardingcirculation of fluid therebetween, means normally restraining rotationof the rotor, a normally unoperated speed responsive device, and meansconnecting the said retarding andrestraining means to the speedresponsive device, whereby operation of the speed responsive devicereleases said retarding and said restraining means.

6. A fluid power transmission device comprising in combination, a bladedimpeller, a rotor, valve means adapted to close the space between theimpeller blades to keep it inactive, a brake holding the rotornon-rotative, centrifugal weights on the impeller operable outwardly toopen said valve means, and means connecting said valve means and brakewhereby operation of said weights opens the valvesand releases thebrake.

7. A fluid power transmittingdevice comprising, in combination, a bladedimpeller, a rotor, valves between the impeller blades closed to keep theimpeller inactive, a brake holding the rotor non-rotative, centrifugalWeights on \the valves operable at a predetermined speed to open thevalves, and operating means between the valves and the brake wherebyoperation of the valves releases the brake.

8. A hydromechanical power transmitting device comprising, animpel1er,'a rotor, butterfly valves between the impeller blades closedto keep the impeller inoperative, a brake holding the rotornon-rotative, centrifugal weights on the stems of the butterfly valvesswingable outwardly at a predetermined speed to open said valves, andmeans connecting the valves and said brake whereby opening said Valvesreleases said brake.

9. The combination, in a hydromechanical power transmitting device, ofan impeller, a rotor, butterfly valves closing the spaces between theimpeller blades, centrifugal weights on the stems of the butterflyvalves swingable about said stems at a predeterminedimpeller speed toopen said valves, pinions on the said valve stems turnable by opening ofsaid valves, a gear in mesh with said pinions, a brake holding saidrotor non-rotative, and means connecting said gear and said brakewhereby turning of said gear releases said brake.

10. In combination, an impeller, a rotor, buth terfly valvesl closingthe spaces between the impeller blades, centrifugal Weights on` thestems of said valves for rotating said valves to open position at apredetermined impeller speed, pinions on said stems, a gear in mesh withsaid pinions, a brake holding said rotor non-rotative but operableaxially to release said rotor, and means operative by rotation of saidgear to create an axial pressure against said brake to release saidbrake.

11. In combination, an impeller, a coaxial rotor, axially parallel stemsbetween the rotor blades, butterfly valves on said stems, centrifugalweights on said stems swingable outwardly to rotate said stems and opensaid valves, pinion segments on said stems, a coaxial gear in mesh withsaid pinion segments, screw and nut means operable axially by rotationof said gear, an axially applied brake holding said rotor non-rotative,and means connecting said screw and nut means to said brake wherebyoperation of said weights opens said valves and releases said brake.

12. Fluid power transmission mechanism comprising, in combination, abladed rotor, a coaxial bladed impeller having shrouds on each side ofthe blades, axially parallel stems between the impeller blades havingrotative bearing in said shrouds, buttery valves on said stems closingthe spaces between the impeller blades, centrifr ugal weights on saidstems outside one of the shrouds and swingable outwardly to rotate saidstems and open said valves, pinion segments on said stems outside theother said shroud, a coaxial gear in mesh with said pinion segments androtatable thereby, screw and nut means associated with said gearoperable axially by rotation of said gear, a brake element carried bysaid rotor urged axially into engagement with a nonrotatalble element tohold said rotor non-rotative, resilient means urging said brake elementaxially into engagement, and means extending from said screw and nutmeans to said brake element operable, by axial movement of said screwand nut means, to move said brake element against said resilient meansto release said brake.

FREDERICK W. CO'I'I'ERMAN.

